Road equipment of this type, although widely used for numerous years, poses considerable installation problems.
In effect, after having erected the parallel walls that delimit the ditch, it is necessary first to install side boards at regular intervals on the facing edges of the walls.
Then, quick-setting concrete pads are poured on each of the walls at the site of these side boards, so as to be able to level the upper surface of the walls.
After drying, the main beams are placed on the pads, and the cover is placed the main beams.
Each wall is then raised by another layer of concrete, so as to bury the base of the main beams.
A final layer of concrete or a layer of asphalt is then poured around the main beams, outside of the cover.
After drying, the cover is withdrawn, and the side boards and their holding elements are extracted.
Under these conditions, the installation of the known road elements is time-consuming and expensive.